Are you guys really talking about healer balancing? Just a hint - there was a druid/warlock brought as a dps some time ago, but since then I saw more healers playing that class than dps players So even if a class is changed/designed as a dps, it can - generally spoken - still be a viable healer class, since - as we all surely agree - heal is "op" these days and should be drastically nerfed to make the secondary class matter.
Conclusion: it doesn't matter at all, which heal class heals the most amount, only the support for the raid matters. From my perspective as a tank, it doesn't matter if I'm healed by a priest/mage or priest/druid or priest/scout or even priest/rogue. The only difference is: my fps don't suck at priest/mage.
If we will get harder ini with a lot of AoE dmg from bosses I'm pretty sure healers go back to the strongest class combos. Honestly i don't see class balance at all, I see dds balance only. I don't see any difference in fps even with d/s, just turn off animations. RoFL isn't a good example if you talking about anything because every endgame party just run ahead and doesn't care about anything.